ac compressor

I have a 1985 cutlass supreme my Ac compressor runs then stop an runs again I'm confuse I don't know what the problem is somebody please help I just hope I don't have to buy a new compressor

The number one failure mode of mobile a/c systems is loss of refrigerant due to a leak. Recover and weigh refrigerant extracted to confirm loss of refrigerant- factory specified amount is on label underhood. Then find and fix your leak- then evacuate (pull vacuum) and recharge to factory spec with the approprite refrigerant.

Hint: compressor shaft seals were very prone to leak on your vehicle- look for oil/greasy area around front of compressor- and slinged out onto nearby surfaces.